a running constant
by displayheartcode
Summary: Those who practice the Art are bound to run into each other across time and space. Just keep your faith, travel hopefully, and the Universe will surprise you. [Crossover]


**a/n: **It's unedited crossover time!

**Disclaimer**: Ha, ha, no.

**Title**: a running constant

**Word Count: **1K

**Summary**: Those who practice the Art are bound to run into each other across time and space. Just keep your faith, travel hopefully, and the Universe will surprise you. [Crossover]

* * *

**i.**

"Hi," said a blonde woman in a drawling Yorkshire accent. They stepped out of a blue police box and placed their hands on their lower back, stretching. "Sorry about that crash. Is it okay if we stop by for a kip?"

Tom, who had been busy watering the plants, blinked. "I'm sorry?"

"Right. _We_. My mates. Fam. Gang." They gestured to the police box and several humanoid figures sheepishly stepped into Tom and Carl's backyard. Some waved, one looked ready to collapse in shock. "We're on errantry and we greet you."

Carl struggled to speak. He looked at the police box, the people, and the alien woman in the long white coat. He then shared a quick glance at his partner. "Sure, we have tea."

"America, again?" one of the companions said, dazed. He appeared older than the rest. "I thought you said we were going to Europa, Doc?"

"Pit stops are important, Graham. And these two" – they gestured to Tom and Carl— "are some of the nicest wizards on this side of the galaxy."

"Wizards?" This time it was the younger man in the group. "But we just dealt with those evil mud witches."

Tom cracked a smile. "The Universe is a weird place."

Carl slid the patio doors open for everyone to enter. "It's an occupational hazard."

**ii.**

The silicon planet sat on what Doctor called the edge of the universe. At least forty-trillion lightyears away, it was later clarified when Ryan asked for more details when they had arrived wandering among the towering volcanic structures that reflected back the stars.

It was beautiful. The polished ground, the glimmer of gold and rust streaks in the strange material, sporadic craters of crushed glass, the dull red star in the horizon burning coolly against the backdrop of a swirling galaxy, but Yaz was trying not to puke on an alien planet.

"Sorry," said the Doctor as they passed a flask full of bubbling cold liquid around. "Gravity is more like what's on Mars here, but it's still a long way out for all of your bodies to adjust to the thin atmosphere. This'll help your stomachs."

Yaz took a deep sip. Graham unwrapped a sandwich from somewhere inside his jacket.

_Forty-trillion lightyears. _

The thought was almost too much.

The doctor paused in mid-speech about trace elements; eyes suddenly wide. They dropped to a crouch and ran their hands across the slick surface, making noises much like a child would on Christmas morning and finding a dream's worth of presents under the tree. Yaz wouldn't know the feeling, but she recognized it from her classmates back in primary school.

"Oh, _brilliant! _Looks like the planet upgraded." Pulling their Sonic from their pocket, the Doctor scanned the ground, laughter bubbling up. The Sonic let out a distressed whirl. "I've never seen a place with so much data."

"Is that a robot turtle walking towards us?" Ryan asked.

"Oh, no," Graham said.

Yaz muttered over the rim of the flask, "Don't have laser eyes, please don't have laser eyes…"

The Doctor waved. "Look, a new friend! Hi, friend!"

**iii.**

"Any sufficiently advanced technology is indistinguishable from magic."

"That's Clark," said Ryan, surprising his grandfather.

The red-haired girl sitting on the steps of the TARDIS smiled faintly. They'd picked up on her distress call from some shambling asteroid. Ryan had been expecting her to be some kind of alien with cyber parts, but she was just as human as he was. Except for the talking laptop that was busy scurrying around on its thin metal legs. He wasn't sure how that was possible.

"Exactly," she said, rising to her feet. She was pale from her adventure but steady enough for Ryan not to worry. "Science, magic, it's all the same. I'm Dairine Callahan and Spot over there is my associate."

The laptop beeped. It twirled in a circle.

"Out on errantry?" the Doctor asked.

Dairine's smile melted away. "The asteroid was heading too close to a developing planet and I…I got a variable mixed up." She winced. "Mistakes like that can get a wizard killed."

"You're safe now," Yaz assured her.

**iv.**

The figure gave them all a cold smile, spreading his pale hands out. "There is no escape." The ground shook and the planet's denizens were screaming. Somewhere off in the distance, Graham swore he felt something crack beneath his feet that was reverberating from the core. The entire planet was on the verge of collapse and their nifty time travel box was nowhere in sight.

"Who are you?" the Doctor demanded. They held their Sonic out like a sword. "And no tricks this time."

Yaz flexed her police baton out by her side, ready to fight. Ryan tensed, ready to join her.

"You already know what I am," he said in the same baritone as before. Now with no need to hide, Graham recognized something terrifying in those eyes, it was almost like looking into his own reflection those days after Grace's funeral. The eyes Time Shaw had. The same anger and rage. "I've burned out stars, destroyed entire planets, I am Death and the end you will all face."

"Fairest and Fallen, greeting and defiance." Something burned in the Doctor's expression. _"Starsnuffer."_

Above them, the planet's sun died.

"Well met, traveler," he said.

**v.**

A phantom image appeared over the console of the TARDIS. Large and reptilian, Yaz wasn't sure what she was looking at, but the Doctor ran over to greet it.

"Mamvish! _Dai stihó!_What brings you here?"

Was it a dinosaur? Yaz tried to be inconspicuous with her staring. Iridescent eyes, pebbled skin, a head that was about four feet wide, but the whole thing kept flickering in and out of existence like it was experiencing a bad signal.

"Well met in haste, friend," it said, going still, the image stabilizing and strange symbols burned over its skin. "But we're running out of time, and as Species Archivist, I am requesting your assistance on behalf of the Powers—"

"I accept," the Doctor interrupted.

Mamvish's eyes swirled. "I haven't even told you the rest."

"Maybe we should hear the rest," Graham agreed.

"No need. I already accept." The Doctor pointed to Yaz and Ryan. "A hallway down from the flamingo, third right, second left, five doors west, you'll find the rafting gear."

**vi.**

A large macaw swooped down and landed on the Doctor's shoulder.

_"Ack!_ You have all the luck," it said in a raspy voice, reminding Ryan of the announcers that his Gran used to listen to on the radio. "New face, I see?"

"Likewise," the Doctor said. They rapped the side of the bird's beak with their knuckles. "Now tell us something useful."

**vii.**

"Can you hear it?" The Doctor leaned out the TARDIS doorway, an entire galaxy sprawled outside, slowly, slowly drifting apart with stars shining and comets racing against the black. "Whole universes are teeming out there, and you can still hear the echo of how it all started. _Listen_. Can you hear that heartbeat?"

The Doctor pressed their cheek to the doorway, sighing. "And it's so beautiful**."**


End file.
